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Natural Metals: On the Surface

Actively influencing natural metal surfaces and sealing them

Pure Freeform Oct18 1

In today’s architecture, one of the more interesting trends of natural metals is to acutely influence their surface and then seal them with a fluoropolymer-based clear coat, ensuring the color and design will not fade.

Although certain projects benefit from the natural oxidation of natural metals where the metal patina is induced by the building’s surroundings, we see trends that are largely driven by designers’ or developers’ desire for the finish to remain unchanged and for the panel and the color to stand the test of time. Typical anodization is a common choice for the latter, but it limits design, color control (based on the batches of metal) and warranty.

New Processes

However, there are new processes that have much more control over the design, utilizing raw aluminum, organic pigments and Lumiflon resins. With a strong attention to texture, reflection and luminosity— all paired with natural colors—this process retains the natural character of the metal, and thus many anticipate this as the future of metal surfacing.

Compared to Kynar, Lumiflon allows for different gloss levels (from a 2 or super matte to 90, nearly reflective), as well as a wider range of colors and textures. This allows for the designer to truly choose a finish that is site specific and contextual, while retaining the beautiful luminosity, reflection and glow expected in a natural metal.

Additionally, the aluminum may be diffused with copper or gold pearl essence, warming up the light reflection and creating a new depth to typical metal panels. Since each batch of aluminum has a natural variation of its raw color, there is a subtle deviation of depth, but certainly less than that of anodization or natural metals. As with all Lumiflon coatings, a 20-year warranty is guaranteed on fade, chalk, gloss and color.

A notable application of these finishing processes is the corrugated metal façade of the Canopy by Hilton Hotel in Portland, Ore., designed by ZGF Architects, Portland. Set in the Pearl District, where cobblestone streets and industrial loading docks juxtapose against galleries, boutiques and cafés, the hotel will feature 153 rooms, event space and an artisanal restaurant. As with any metal finish created using clear-coat technology, the appearance of the panels changes throughout the day according to the angle and intensity of sunlight.

Geoff Hahn is creative director for Pure + FreeForm, Oakdale, Minn. To learn more, visit or email